Four cylinders — no waiting
Becoming increasingly powerful, more than one-third of all new cars now come with four-cylinder engines
Four-cylinder engines, once almost exclusively limited to small economy cars, have gone mainstream. According to Experian Automotive in Schaumburg, Illinois, an industry leading 37.7 percent of all new light duty vehicles sold in the U.S. now come fitted with four-cylinder engines. That’s up from 30.4 percent of the market in 2010 and a mere 7 percent back in 1975.
While four-cylinder engines are being used more extensively these days to help automakers meet increasingly strict federal fuel economy goals, thanks to the latest engine designs smaller doesn’t necessarily mean slower. In fact, today’s four-cylinder engines are as strong as yesterday’s six-cylinder — and even eight-cylinder — powerplants. According to Experian data, the average four-cylinder engine now produces 168 horsepower, versus a mere 115 horsepower back in 1998 — that’s when the average V8 engine netted just 188 horses.
Combining direct fuel injection and turbocharging enables smaller engines to become as muscular as larger — and less fuel-efficient — ones, with plenty of torque on hand to ensure quick launches and ample highway passing power. Direct injection, in which fuel is shot into each of an engine’s cylinders at a greater than normal pressure, affords a higher compression ratio, which in turn boosts fuel economy. While the turbocharger — which forces additional air into an engine’s cylinders to wring more power out of an engine — has been around for decades, direct injection enables it to operate at peak efficiency.
What’s more, a four-cylinder engine typically weighs 100-150 pounds less than a larger V6, and trimming excess pounds from a vehicle is the easiest way to increase its fuel economy. Automakers are on a mission to slash weight out of each of their models to help meet stricter federal mileage requirements that are being phased in over the coming years. All else being equal, decreasing a vehicle’s weight by 10 percent enables close to a three percent increase in fuel economy. Installing a moreefficient engine that’s able to maintain the same level of performance at the lighter weight can result in around a 7.5 percent savings.
Yet another benefit of using a smaller engine is that it places less weight over the front wheels, which will tend to make the vehicle feel livelier through the curves than the same model equipped with a larger and heavier engine.
Thus, turbo-fours have now supplanted V6s in many midsize passenger cars, including the Chevrolet Malibu, Hyundai Sonata and Kia Optima, and can be found in what once would have been considered unlikely vehicles. These include bona fide muscle cars like the Chevrolet Camaro and Ford Mustang, where their available turbo-fours produce 275 and 310 horsepower, respectively. Either car can reach 60 mph in a reasonably quick 5.5 seconds with four cylinders under the hood and get an estimated 30-mpg on the highway. As a matter of reference, the strongest V8 engines in the 1990-vintage versions of those two sporty cars were rated at a relatively meek 245 horsepower (Camaro) and 225 horsepower (Mustang).
On the truck side of the new-car market, the latest version of Mazda’s seven-passenger CX-9 crossover SUV can only be fitted a turbofour. This 2.5-liter powerplant nets 250 horsepower with an energetic 310 pound-feet of torque and is EPA-rated to achieve 22/28-mpg city/highway.
“The option of a small vehicle with good fuel economy has always had a significant appeal to consumers. The advances we’ve seen in horsepower and fuel efficiency among these vehicles are very encouraging,” says Brad Smith, Experian’s director of automotive data and analytics.